1. Field of the Invention
The present invention relates to apparatus and methods in the field of isolated, physically contact-free wafer processing and more specifically to a two-sided wafer processing, enabling the combination of an optimal wafer processing of one flat side of the wafer together with an accompanying removal of contamination from the other, opposite side of this wafer, as a requirement for the advanced production of wafers with feature size of 1 .mu.m and below.
2. Description of the Prior Art
Advanced, two-sided wafer processing, taking place within a smallest sized wafer processing chamber without any mechanical moving component in this chamber provides an improved performance condition for such processing.
Such processing as well as apparatus for practicing the two-sided wafer processing are disclosed in Patent Applications Nos. NL-A-8601 254 and WO-A-87/04853 of Applicants.
In these apparatus a direct and continuous downward discharge, whether or not through a wide circumferential discharge passage, takes place of the processing medium, supplied into the processing chamber and expelled in lateral direction from both mini wafer processing gaps of the chamber on top and underneath the wafer.
Thereby the following shortcomings of these apparatus:
1. Because of the continuous discharge, the consumption of processing medium is considerable;
2. By solely moving the processing medium in lateral direction along the wafer surface, the processing efficiency is low;
3. In the central section of the processing gaps the processing efficiency is considerably higher than near the lateral outside of the wafer;
4. The required use of medium supply grooves in both upper and lower wall, extending in lateral direction from these supply channels toward close to the lateral outside of the wafer to maintain the floating condition, with locally at these grooves a reduced processing efficiency of the processing medium;
5. The use of medium supply channels in the vertical sidewall of the processing chamber for urging gaseous medium toward the wafer edge for a physically contact-free wafer processing and by means of wafer rotation a more uniform wafer processing; and
6. A relatively high consumption of gaseous medium.